Pressure actuated switch



Sept. 13, 1932 w. c. HEATH 1,875,925

PRESSURE ACTUATED SWITCH Filed May $7, 1927 3 Sheeis-Sheet l o 1-7 g \l O; INVENTOR Mum/n CHE/77b ATTORNEY Sept.'13, 1932. w. c. HEATH 1,376,926

PRESSURE ACTUATED SWITCH Filed May 27. 1927 S'SheetS-Sheet 2 l ww wk v X w .m& m. \N

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Mum/w C. HEHT/l ATTORNEY Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE WILLIAM C. HEATH, OF BELOIT, WISCONSIN, ASSIGNOR '10 FAIRBANKS, MORSE & 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS PRESSURE ACTUATED SWITCH REISSUED Application filed May 27, 1927. Serial No. 194,682.

This invention relates to pressure actuated, circuit control means, and especially to pres sure control switches for motors operating fluid pumps.

An object of this invention is to provide a pressure switch, in which friction is minimized, which has a. maximum speed of operation and a positive switch action, especially for opening the circuit.

A further object of this invention is to provide a switch which is compact and yet easily accessible.

A still further object of this invention is the provision of a pressure switch having more than the usual electrical capacity, and which will afford better protection of live parts from grounds or short circuits, than is found in existing types of such switches.

A still further object is the provision of a pressure switch of such construction that the ease of manufacture and assembly of component parts will result in an unusually low production and repair cost.

Further objects and advantages of this invention will appear from the drawings and the following detailed description.

Referringto the drawings, Fig. 1 is an enlarged plan view'of my switch assembly, with the cover removed; Fig. 2 is a sectional elevation taken along the line 2-2 of Fig. 1, and outlining diagrammatically the movement of certain moving parts; Fig. 3 is a sectional elevation taken along line 3-3 of Fig. 1; Fig. 4 is an elevation in perspective of a preferred form of oscillator; Fig. 5 is an end elevation of a preferred form of tumbler, and Fig. 6 is a sectional elevation, taken along line 6-6 in Fig. 1. Certain elevational details have been omitted fromthis figure for the sake of clearness.

Referring by numerals to the drawings,

represents a frame which may be die-cast of suitable material and preferably mounted, as shown in '2, upon a base 21. The

lower extremity of the base is tapped at 22 to receive a pipe or other connection with the fluid pressure. The fluid pressure source (not shown) may consist of a pump chamber or a suitable air pressure tank, with or without pipe connections. Between frame 20 and phragm 'a hinge or pivot base 21 is preferably located a diaphragm 23 upon which thefluid pressure acts, to operate the switch mechanism. The fluid under pressure may be introduced directly through an orifice cleaner 24. inserted loosely in a orifice 25. The cleaner 24 is preferably made of aluminum or some other light, non-corrosive metal or material. The fluid pressure against dlaphragm 23 is transmitted to a plunger 26 and thence to a socket 27 which is preferably aflixed to lever 28. This lever is preferably pivoted at 29 to frame 20. Lever 28 may be made of sheet steel or other suitable material. On a side opposite pivot 29, lever 28 carries a heavy coil spring 31, which'tends to depress lever 28 as far as the position of dia- 23 will permit. Spring 31 is preferably positioned over a stud bolt 32, retention and adjustment of this spring being provided by a knurled nut 33 on the upper end of bolt 32. The stud bolt 32 is preferably threaded into frame 20 and carried thereby.

- The lever 28 is preferably in connection with a spring 35 which may be hooked onto or otherwise secured to the lever at point 34. In operation, point 3 l'moves in an arc, the radius of which equals or exceeds the distance between centers of pivot 29 and the pivot 37, hereinafter described. I At the opposite end, spring 35 is preferably adjustably attached to a U-shaped oscillator 36. At the opposite end of the oscillator 36 is preferably 37 about which the oscillator is free to rotate between limits pointed out at 38 and 39. (See Fig. 2.) Limits 38 and 39 are located substantially at equal distances from a line between the pivots 29 and 37 A Ateach end of the material of required strength. To the brush carriers 44 are preferably secured brush holders 45, which I prefer to form of sheet brass and to fasten by riveting or otherwise securing them to the carriers 44. Brush holders 45 carry brushes 46. The brushes are so shaped as to retain loosely their position in the brush holders 45. The brushes preferably consist of a plurality of thin pieces of sheet bronze, but may be formed of any other flexible conducting material. At 43 I have indicated a preferred arrangement of the contact pieces in the path of the brushes 46. These are recessed within and affixed to porcelain pieces 47. These contact pieces 43 are preferably formed of sheet brass, but may be made of any suitable conducting material. Binding screws 42 are provided for the usual electrical connections. Suitable wires or leads 49 may be introduced through insulating conduits, such as hard rubber tubes 48. A bracket 50 may be located as shown and formed of sheet steel or other suitable material, which is drilled to receive and support an oscillator hinge or pivot 37, and hence supports the oscillator 36.

The above detailed description of the com ponent parts of the switch has been confined to the novel portions of the assembly and such as will be pertinent to a description of its operation. The necessary details of construction, such as fastening and holding means, may be readily supplied by those skilled in the art and will be implied from the foregoing description of the major elements of the assembly.

A cover 52 may be provided as a convenient means of protecting and enclosing the switch parts. Where the switch is enclosed in a larger chamber or container, such a cover may be dispensed with. It will be seen that the form of the base and design of the switch parts are such that the cover 52 may be a simple sheet metal enclosure of cylindrical I form, having a closed top.

The operation of my device is thought to be apparent from the foregoing description of parts. A source'of fluid pressure is presupposed, such as is found in pressure water systems, in refrigeration equipment and the like. The diaphragm 23 is subjected to fluid pressure either through orifice 25, which is preferably an opening slightly larger than the diameter of orifice cleaner 24. The movement of the cleaner 24 in the orifice 25 serves to prevent the entrance of foreign matter through the orifice, and serves to eliminate a prevailing difficulty in the operation of pressure control switches.

As fluid pressure increases, the diaphragm 23 raises, and acting through plunger 26, lifts lever 28 against the pressure of spring 31. The lever is pivoted about the stationary piv- 0t 29, and hencepoint 34 at which the spring 35 isattached, will be moved on an are, a short distance to the left and upwardly (in Fig. 2). Oscillator 36 is mounted on a pivot 37 carried in the frame. The effect of the upward movement of lever 28 and point 34 is thus to rotate the lower end of oscillator 36 to the left (in the figure) to point 38, the limit of movement in this direction.

The initial movement of the oscillator has no effect on movement of the tumbler. As the oscillator continues moving to the left, it impinges upon the tumbler 40, and the tumbler is partially rotated, its movement being relayed from the oscillator. The tumbler 40 carries the cross bar 41, on which are mounted the brush carriers 44 and holders 45, with brushes 46. Movement of the tumbler to the left (Fig. 2) thus raises the cross bar 41, and the brushes 46 are quickly raised from the contacts 43 to open the motor or other circuit.

The switch is illustrated in an intermediate position (in Fig. 2), at a time when spring 35 is under greatest tension and when the oscil lator 36 is between its extreme positions. Spring 35 thus tends to move the oscillator toward point 38 or point 39 with a snap action.

The tumbler 40, with its connected parts, the cross bar 41, brush carriers 44, holders 45 and brushes 46, are positioned by the auxiliary springs 51, which serve to maintain the brushes either on, or away from the contacts while the oscillator is in a non-actuating position, before it picks up the tumbler 40. From the dotted lines appearing in Fig. 6, it will be seen that the center line of each spring 51 will fall above or below the hinge 37, and that these springs will position the tumbler to keep the brushes on the contacts, as in Fig. 4, or away from them. Obviously the springs 51, through their action on the tumbler, insure a quick movement of the brushes in either direction between open and closed position of the switch.

It will be obvious that the described arrangement of the oscillator and tumbler, with the springs, provides a necessary range of movement of lever 28 and oscillator 36, so that an appreciable fluctuation of pressure must occur before any movementis imparted to tumbler 40 and the brushes, either to open or to close the switch. The effect of both the spring 35 and auxiliary springs 51 is to make or break contact quickly and positively, by

giving a hammer effect to the oscillator, which operates by impact against the tumbler. This quick action is aided both in opening and closing the switch by the weight of certain of the moving parts of the assembly.

The operation of the assembly for closing the switch is analogous to that for opening except that the direction of movement of parts is reversed. As pressure decreases, the spring 31, bearing directly'against lever 28, moves the lever downwardly and point 34 moves downwardly and to the right, (in Fig.

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5 a quantity production basis.

2). Acting through spring 35, the lever then moves the oscillator 36 to bring its lower por-- tion to point 39. Toward the end of this movement the oscillator motion is relayed to thetumbler 40. The tumbler then quickly moves the cross bar 41 with the brush carriers and brushes down onto contact pieces 43 to close the circuit.

Adjustment is preferably provided on spring 31 by the knurled nut 33 on threaded stud 32. A further adjustment may be provided by varying the tension of spring 35, which actuates the oscillator 36. This adj ustment may be, as shown, an ordinary screw thread adjustment in the connecting portion of the oscillator 36. Such adjustments are found necessary to provide for differences in fluid pressure range, and to cover the regulation of the relay action of the switch.

It will be seen that I have provided an automatic pressure switch assembly which is compact, reliable and inexpensive to manufacture. In my device each of the wearing parts is of such form as to be easily made on The bearing I surfacesare more than ample, and frictional resistance is thus minimized. In certain prevailing types of fluid pressure switches the electrical capacity has been sacrificed in favor of compactness. It will beseen that in of the switch.

my switch construction I have provided a double contact arrangement for each switch pole and in this manner have materially increased the electrical capacity and life of the contact members, as compared with older types of switches in which a single brushand contact are used for each switch pole.

The assembly is so designed throughout that the wear resulting from years of service will not affect the quick and positive action Although my invention consists largely in the construction and arrangement of parts hereinbefore described and particularly pointed out in the claims, yet I do not limit my invention to the precise form or construction of parts shown or the several parts thereof,-inasmuch as various alterations may be made without changing the scope of my invention.

What I claim is:

1. In a pressure controlled apparatus, a flexible element having a surface disposed in a fluid pressure passage and positionable according to the fluid pressure therein, a cleaning member operable in said passage responsively to movements of said flexible element, a lever movable by the flexible element, an oscillating member operatively associated with the lever, a control element movable by the oscillating member, and means providing a limited movement of the oscillating member free of operative engagement with the cont-r01 element.

2'.'In a fluid pressure control, a base having a fluid admission orifice, a diaphragm, an orifice cleaner on one side of the diaphragm and movable responsively to movements of the diaphragm, a lever on the opposite side of the diaphragm, adapted to be moved by variation in fluid pressure on said diaphragm, an oscillator, an extensible connection between the lever and the oscillator,

and a control actuating member disposed in a limited portion of the path of the oscillator.

3. In a fluid ressure control, a base having a pressure uid admission orifice, a diaphragm, a spring opposing the outward movement of said diaphragm, an orifice cleaner adjacent one side of the diaphragm and movable responsively to movements of the diaphragm, a lever on the opposite side of the diaphragm, the lever adapted to be actuated by fluctuation ofpressure against said diaphragm and by the spring, an oscillator, an adjustable spring connecting the lever and the oscillator, and a control member so disposed with respect to the oscillator that the member and the oscillator each has a limited free angular movement.

4. In a control device adapted for operation by fluid pressure, a diaphragm, a base having a pressure admission passage, a lever operatively associated with the diaphragm, a cleaning member carried by the diaphragm, and extending into said passage, an oscillator, a spring connecting the lever and oscillator, a tumbler disposed across a portion of the path of movement of the oscillator, and a control member carried by the tumbler.

5. In a hydraulic pressure control device, a diaphragm, a fluid passage adjacent one side of the diaphragm, a cleaning member operable with the diaphragm and extending into said passage, a lever operatively associated with the diaphragm, a control operating member, and means operatively connecting said member and lever in lost-motion engagement.

6. In a fluid pressure control, a base having a fluid admission orifice, a diaphragm arranged to be subjected to a source of fluid,

the pressure of which is to be controlled, an orifice cleaner on one side of the diaphragm, and movable responsively to'movements of the diaphragm, a lever pivoted adjacent the opposite side-of the diaphragm, adapted to be moved by variation in fluid pressure on said diaphragm, an oscillator, an extensible connection between the lever and the oscillator, and a control actuating member havment thereof in either direction from an intermediate position.

7. In a fluid pressure control, a base haviao ing a pressure-fluid admission orifice, a diaphragm, a spring opposing the outward movement of said diaphragm, an orifice cleaner adjacent one side of the diaphragm and movable responsively to movements of the diaphragm, a lever in pivoted relation to the base on the opposite side of the diaphragm, the lever adapted to be actuated in one direction by fluctuation of pressure against said diaphragm, and in the opposite direction by the spring, an oscillator, an adjustable spring connecting the lever and the oscillator, and a control operating member having spaced seats for selective, impacting engagement by opposite sides of the oscillator, said seats being so spaced and disposed With respect to the oscillator that the member and the oscillator each is adapted for a limited angular movement free of engagement With the other.

8. In a control device adapted for operation by fluid pressure, a diaphragm, a base having a pressure admission passage, a lever pivotally related to the base, and operatively associated with the diaphragm, a cleaning member carried by the diaphragm and extending into said passage, an oscillator, a spring connecting the lever and oscillator, a tumbler disposed across opposite end portions of the path of movement of the oscillator, and characterized by spaced seats adapted to be impactively engaged, one at a time, by the oscillator, and a control member carried by the tumbler.

WVILLIAM C. 

